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<pre><span class="sourceLineNo">001</span>package imagingbook.calibration.zhang;<a name="line.1"></a>
<span class="sourceLineNo">002</span><a name="line.2"></a>
<span class="sourceLineNo">003</span>import java.awt.geom.Point2D;<a name="line.3"></a>
<span class="sourceLineNo">004</span>import java.util.Arrays;<a name="line.4"></a>
<span class="sourceLineNo">005</span><a name="line.5"></a>
<span class="sourceLineNo">006</span>import org.apache.commons.math3.analysis.MultivariateMatrixFunction;<a name="line.6"></a>
<span class="sourceLineNo">007</span>import org.apache.commons.math3.analysis.MultivariateVectorFunction;<a name="line.7"></a>
<span class="sourceLineNo">008</span>import org.apache.commons.math3.fitting.leastsquares.LeastSquaresFactory;<a name="line.8"></a>
<span class="sourceLineNo">009</span>import org.apache.commons.math3.fitting.leastsquares.LeastSquaresOptimizer.Optimum;<a name="line.9"></a>
<span class="sourceLineNo">010</span>import org.apache.commons.math3.fitting.leastsquares.LevenbergMarquardtOptimizer;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import org.apache.commons.math3.fitting.leastsquares.MultivariateJacobianFunction;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import org.apache.commons.math3.linear.ArrayRealVector;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import org.apache.commons.math3.linear.RealVector;<a name="line.13"></a>
<span class="sourceLineNo">014</span><a name="line.14"></a>
<span class="sourceLineNo">015</span>/**<a name="line.15"></a>
<span class="sourceLineNo">016</span> * Abstract super-class for non-linear optimizers used for<a name="line.16"></a>
<span class="sourceLineNo">017</span> * final, overall optimization of calibration parameters.<a name="line.17"></a>
<span class="sourceLineNo">018</span> * The actual optimization is performed by the sub-classes.<a name="line.18"></a>
<span class="sourceLineNo">019</span> * @author WB<a name="line.19"></a>
<span class="sourceLineNo">020</span> */<a name="line.20"></a>
<span class="sourceLineNo">021</span>public abstract class NonlinearOptimizer {<a name="line.21"></a>
<span class="sourceLineNo">022</span><a name="line.22"></a>
<span class="sourceLineNo">023</span>        private static int maxEvaluations = 1000;<a name="line.23"></a>
<span class="sourceLineNo">024</span>        private static int maxIterations = 1000;<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>        protected final Point2D[] modelPts;<a name="line.26"></a>
<span class="sourceLineNo">027</span>        protected final Point2D[][] obsPts;<a name="line.27"></a>
<span class="sourceLineNo">028</span>        protected final int M;          // number of views<a name="line.28"></a>
<span class="sourceLineNo">029</span>        protected final int N;          // number of model points<a name="line.29"></a>
<span class="sourceLineNo">030</span>        protected int camParLength;             // number of camera parameters (7)<a name="line.30"></a>
<span class="sourceLineNo">031</span>        protected int viewParLength;    // number of view parameters (6)<a name="line.31"></a>
<span class="sourceLineNo">032</span><a name="line.32"></a>
<span class="sourceLineNo">033</span>        private Camera initCam = null;<a name="line.33"></a>
<span class="sourceLineNo">034</span>        private Camera finalCamera = null;<a name="line.34"></a>
<span class="sourceLineNo">035</span>        private ViewTransform[] initViews = null;<a name="line.35"></a>
<span class="sourceLineNo">036</span>        private ViewTransform[] finalViews = null;<a name="line.36"></a>
<span class="sourceLineNo">037</span><a name="line.37"></a>
<span class="sourceLineNo">038</span>        protected NonlinearOptimizer(Point2D[] modelPts, Point2D[][] obsPts) {<a name="line.38"></a>
<span class="sourceLineNo">039</span>                this.modelPts = modelPts;<a name="line.39"></a>
<span class="sourceLineNo">040</span>                this.obsPts = obsPts;<a name="line.40"></a>
<span class="sourceLineNo">041</span>                this.M = obsPts.length;<a name="line.41"></a>
<span class="sourceLineNo">042</span>                this.N = modelPts.length;<a name="line.42"></a>
<span class="sourceLineNo">043</span>        }<a name="line.43"></a>
<span class="sourceLineNo">044</span><a name="line.44"></a>
<span class="sourceLineNo">045</span>        /**<a name="line.45"></a>
<span class="sourceLineNo">046</span>         * Performs Levenberg-Marquardt non-linear optimization to get better<a name="line.46"></a>
<span class="sourceLineNo">047</span>         * estimates of the parameters.<a name="line.47"></a>
<span class="sourceLineNo">048</span>         * @param initCam the initial camera parameters<a name="line.48"></a>
<span class="sourceLineNo">049</span>         * @param initViews the initial view transforms<a name="line.49"></a>
<span class="sourceLineNo">050</span>         */<a name="line.50"></a>
<span class="sourceLineNo">051</span>        protected void optimize(Camera initCam, ViewTransform[] initViews) {<a name="line.51"></a>
<span class="sourceLineNo">052</span>                this.initCam = initCam;<a name="line.52"></a>
<span class="sourceLineNo">053</span>                this.initViews = initViews;<a name="line.53"></a>
<span class="sourceLineNo">054</span>                this.camParLength = initCam.getParameterVector().length;<a name="line.54"></a>
<span class="sourceLineNo">055</span>                this.viewParLength = initViews[0].getParameters().length;<a name="line.55"></a>
<span class="sourceLineNo">056</span><a name="line.56"></a>
<span class="sourceLineNo">057</span>                MultivariateVectorFunction V = makeValueFun();<a name="line.57"></a>
<span class="sourceLineNo">058</span>                MultivariateMatrixFunction J = makeJacobianFun();<a name="line.58"></a>
<span class="sourceLineNo">059</span><a name="line.59"></a>
<span class="sourceLineNo">060</span>                RealVector start = makeInitialParameters();<a name="line.60"></a>
<span class="sourceLineNo">061</span>                RealVector observed = makeObservedVector();<a name="line.61"></a>
<span class="sourceLineNo">062</span>                <a name="line.62"></a>
<span class="sourceLineNo">063</span>                MultivariateJacobianFunction model = LeastSquaresFactory.model(V, J);<a name="line.63"></a>
<span class="sourceLineNo">064</span>                LevenbergMarquardtOptimizer lm = new LevenbergMarquardtOptimizer();<a name="line.64"></a>
<span class="sourceLineNo">065</span>                Optimum result = lm.optimize(LeastSquaresFactory.create(<a name="line.65"></a>
<span class="sourceLineNo">066</span>                                model,<a name="line.66"></a>
<span class="sourceLineNo">067</span>                                observed, <a name="line.67"></a>
<span class="sourceLineNo">068</span>                                start, <a name="line.68"></a>
<span class="sourceLineNo">069</span>                                null, <a name="line.69"></a>
<span class="sourceLineNo">070</span>                                maxEvaluations, <a name="line.70"></a>
<span class="sourceLineNo">071</span>                                maxIterations));<a name="line.71"></a>
<span class="sourceLineNo">072</span>                <a name="line.72"></a>
<span class="sourceLineNo">073</span>//              System.out.println(NonlinearOptimizer.class.getSimpleName() + "; iterations = " + result.getIterations());<a name="line.73"></a>
<span class="sourceLineNo">074</span>                updateEstimates(result.getPoint());<a name="line.74"></a>
<span class="sourceLineNo">075</span>        }<a name="line.75"></a>
<span class="sourceLineNo">076</span><a name="line.76"></a>
<span class="sourceLineNo">077</span>        /**<a name="line.77"></a>
<span class="sourceLineNo">078</span>         * To be implemented by subclasses.<a name="line.78"></a>
<span class="sourceLineNo">079</span>         * @return a vector value function<a name="line.79"></a>
<span class="sourceLineNo">080</span>         */<a name="line.80"></a>
<span class="sourceLineNo">081</span>        abstract MultivariateVectorFunction makeValueFun();<a name="line.81"></a>
<span class="sourceLineNo">082</span>        <a name="line.82"></a>
<span class="sourceLineNo">083</span>        /**<a name="line.83"></a>
<span class="sourceLineNo">084</span>         * To be implemented by subclasses.<a name="line.84"></a>
<span class="sourceLineNo">085</span>         * @return a Jacobian function<a name="line.85"></a>
<span class="sourceLineNo">086</span>         */<a name="line.86"></a>
<span class="sourceLineNo">087</span>        abstract MultivariateMatrixFunction makeJacobianFun();<a name="line.87"></a>
<span class="sourceLineNo">088</span>        <a name="line.88"></a>
<span class="sourceLineNo">089</span>        <a name="line.89"></a>
<span class="sourceLineNo">090</span>        /**<a name="line.90"></a>
<span class="sourceLineNo">091</span>         * Common value function for optimizers defined in sub-classes.<a name="line.91"></a>
<span class="sourceLineNo">092</span>         */<a name="line.92"></a>
<span class="sourceLineNo">093</span>        protected class ValueFun implements MultivariateVectorFunction {<a name="line.93"></a>
<span class="sourceLineNo">094</span>                <a name="line.94"></a>
<span class="sourceLineNo">095</span>                @Override<a name="line.95"></a>
<span class="sourceLineNo">096</span>                public double[] value(double[] params) {<a name="line.96"></a>
<span class="sourceLineNo">097</span>                        final double[] a = Arrays.copyOfRange(params, 0, camParLength);<a name="line.97"></a>
<span class="sourceLineNo">098</span>                        final Camera cam = new Camera(a);<a name="line.98"></a>
<span class="sourceLineNo">099</span>                        final double[] Y = new double[2 * M * N];<a name="line.99"></a>
<span class="sourceLineNo">100</span>                        int c = 0; <a name="line.100"></a>
<span class="sourceLineNo">101</span>                        for (int m = 0; m &lt; M; m++) {<a name="line.101"></a>
<span class="sourceLineNo">102</span>                                int q = camParLength + m * viewParLength;<a name="line.102"></a>
<span class="sourceLineNo">103</span>                                double[] w = Arrays.copyOfRange(params, q, q + viewParLength);<a name="line.103"></a>
<span class="sourceLineNo">104</span>                                ViewTransform view = new ViewTransform(w);<a name="line.104"></a>
<span class="sourceLineNo">105</span>                                for (int n = 0; n &lt; N; n++) {<a name="line.105"></a>
<span class="sourceLineNo">106</span>                                        double[] uv = cam.project(view, modelPts[n]);<a name="line.106"></a>
<span class="sourceLineNo">107</span>                                        Y[c * 2 + 0] = uv[0];<a name="line.107"></a>
<span class="sourceLineNo">108</span>                                        Y[c * 2 + 1] = uv[1];<a name="line.108"></a>
<span class="sourceLineNo">109</span>                                        c = c + 1;<a name="line.109"></a>
<span class="sourceLineNo">110</span>                                }<a name="line.110"></a>
<span class="sourceLineNo">111</span>                        }<a name="line.111"></a>
<span class="sourceLineNo">112</span>                        return Y;<a name="line.112"></a>
<span class="sourceLineNo">113</span>                }<a name="line.113"></a>
<span class="sourceLineNo">114</span>        }<a name="line.114"></a>
<span class="sourceLineNo">115</span><a name="line.115"></a>
<span class="sourceLineNo">116</span>        // ---------------------------------------------------------------------<a name="line.116"></a>
<span class="sourceLineNo">117</span><a name="line.117"></a>
<span class="sourceLineNo">118</span>        private RealVector makeInitialParameters() {<a name="line.118"></a>
<span class="sourceLineNo">119</span>                double[] s = initCam.getParameterVector();<a name="line.119"></a>
<span class="sourceLineNo">120</span>                double[] c = new double[s.length + M * viewParLength];<a name="line.120"></a>
<span class="sourceLineNo">121</span><a name="line.121"></a>
<span class="sourceLineNo">122</span>                // insert camera parameters at beginning of c<a name="line.122"></a>
<span class="sourceLineNo">123</span>                System.arraycopy(s, 0, c, 0, s.length);<a name="line.123"></a>
<span class="sourceLineNo">124</span><a name="line.124"></a>
<span class="sourceLineNo">125</span>                // insert M view parameters<a name="line.125"></a>
<span class="sourceLineNo">126</span>                int start = s.length;<a name="line.126"></a>
<span class="sourceLineNo">127</span>                for (int i = 0; i &lt; M; i++) {<a name="line.127"></a>
<span class="sourceLineNo">128</span>                        double[] w = initViews[i].getParameters();<a name="line.128"></a>
<span class="sourceLineNo">129</span>                        System.arraycopy(w, 0, c, start, w.length);<a name="line.129"></a>
<span class="sourceLineNo">130</span>                        start = start + w.length;<a name="line.130"></a>
<span class="sourceLineNo">131</span>                }<a name="line.131"></a>
<span class="sourceLineNo">132</span>                return new ArrayRealVector(c);<a name="line.132"></a>
<span class="sourceLineNo">133</span>        }<a name="line.133"></a>
<span class="sourceLineNo">134</span><a name="line.134"></a>
<span class="sourceLineNo">135</span><a name="line.135"></a>
<span class="sourceLineNo">136</span>        /**<a name="line.136"></a>
<span class="sourceLineNo">137</span>         * Stack the observed image coordinates of the calibration pattern points into<a name="line.137"></a>
<span class="sourceLineNo">138</span>         * a vector.<a name="line.138"></a>
<span class="sourceLineNo">139</span>         * @return the observed vector<a name="line.139"></a>
<span class="sourceLineNo">140</span>         */<a name="line.140"></a>
<span class="sourceLineNo">141</span>        protected RealVector makeObservedVector()       {<a name="line.141"></a>
<span class="sourceLineNo">142</span>                double[] obs = new double[M * N * 2];<a name="line.142"></a>
<span class="sourceLineNo">143</span>                for (int i = 0, k = 0; i &lt; M; i++) {<a name="line.143"></a>
<span class="sourceLineNo">144</span>                        for (int j = 0; j &lt; N; j++, k++) {<a name="line.144"></a>
<span class="sourceLineNo">145</span>                                obs[k * 2 + 0] = obsPts[i][j].getX();<a name="line.145"></a>
<span class="sourceLineNo">146</span>                                obs[k * 2 + 1] = obsPts[i][j].getY();<a name="line.146"></a>
<span class="sourceLineNo">147</span>                        }<a name="line.147"></a>
<span class="sourceLineNo">148</span>                }<a name="line.148"></a>
<span class="sourceLineNo">149</span>                // obs = [u_{0,0}, v_{0,0}, u_{0,1}, v_{0,1}, ..., u_{M-1,N-1}, v_{M-1,N-1}]<a name="line.149"></a>
<span class="sourceLineNo">150</span>                return new ArrayRealVector(obs); <a name="line.150"></a>
<span class="sourceLineNo">151</span>        }<a name="line.151"></a>
<span class="sourceLineNo">152</span><a name="line.152"></a>
<span class="sourceLineNo">153</span>        private void updateEstimates(RealVector parameters) {<a name="line.153"></a>
<span class="sourceLineNo">154</span>                double[] c = parameters.toArray();<a name="line.154"></a>
<span class="sourceLineNo">155</span>                double[] s = Arrays.copyOfRange(c, 0, camParLength);<a name="line.155"></a>
<span class="sourceLineNo">156</span>                finalCamera = new Camera(s);<a name="line.156"></a>
<span class="sourceLineNo">157</span><a name="line.157"></a>
<span class="sourceLineNo">158</span>                finalViews = new ViewTransform[M];<a name="line.158"></a>
<span class="sourceLineNo">159</span>                int start = s.length;<a name="line.159"></a>
<span class="sourceLineNo">160</span>                for (int i = 0; i &lt; M; i++) {<a name="line.160"></a>
<span class="sourceLineNo">161</span>                        double[] w = Arrays.copyOfRange(c, start, start + viewParLength);<a name="line.161"></a>
<span class="sourceLineNo">162</span>                        finalViews[i] = new ViewTransform(w);<a name="line.162"></a>
<span class="sourceLineNo">163</span>                        start = start + w.length;<a name="line.163"></a>
<span class="sourceLineNo">164</span>                }<a name="line.164"></a>
<span class="sourceLineNo">165</span>        }<a name="line.165"></a>
<span class="sourceLineNo">166</span>        <a name="line.166"></a>
<span class="sourceLineNo">167</span>        /**<a name="line.167"></a>
<span class="sourceLineNo">168</span>         * Returns the optimized camera parameters.<a name="line.168"></a>
<span class="sourceLineNo">169</span>         * @return the optimized camera parameters<a name="line.169"></a>
<span class="sourceLineNo">170</span>         */<a name="line.170"></a>
<span class="sourceLineNo">171</span>        protected Camera getFinalCamera() {<a name="line.171"></a>
<span class="sourceLineNo">172</span>                return finalCamera;<a name="line.172"></a>
<span class="sourceLineNo">173</span>        }<a name="line.173"></a>
<span class="sourceLineNo">174</span><a name="line.174"></a>
<span class="sourceLineNo">175</span>        /**<a name="line.175"></a>
<span class="sourceLineNo">176</span>         * Returns the optimized view parameters.<a name="line.176"></a>
<span class="sourceLineNo">177</span>         * @return the optimized view parameters<a name="line.177"></a>
<span class="sourceLineNo">178</span>         */<a name="line.178"></a>
<span class="sourceLineNo">179</span>        protected ViewTransform[] getFinalViews() {<a name="line.179"></a>
<span class="sourceLineNo">180</span>                return finalViews;<a name="line.180"></a>
<span class="sourceLineNo">181</span>        }<a name="line.181"></a>
<span class="sourceLineNo">182</span>        <a name="line.182"></a>
<span class="sourceLineNo">183</span>}<a name="line.183"></a>




























































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